Research Newsletter-Spring/Summer 2006

Oxygen Club of California Annual Meeting

The Oxygen Club of California held its annual scientific
conference, co-sponsored by LPI, in Santa Barbara,
California, in mid-April. Oxidants and Antioxidants in Biology
featured 35 presentations in four sessions: "Obesity,
the Metabolic Syndrome, and Oxidative Stress"; "Obesity,
Uncoupling Proteins, and Micronutrient Action"; "Dietary
Modulation of Cell Signaling Pathways"; and "Mitochondrial
Function, Aging, and Disease."

Addressing obesity, several speakers noted that it is
associated with inflammation and oxidative stress, which
can be ameliorated with weight loss and decreased
macronutrient intake. Additionally, fish oil (eicosapentaenoic
acid [EPA] and docosahexaenoic acid [DHA]) exerts antiinflammatory
effects that may reduce the risk of heart
disease in obese individuals. Insulin resistance and
inflammation are also associated with obesity in pregnant
women, increasing the risk for gestational diabetes.
Insulin resistance, oxidative stress, and dysfunction of the
insulin-producing pancreatic beta cells may be attenuated
with alpha-lipoic acid and acetyl-L-carnitine. Selenium
supplementation in rats alleviated inflammation associated
with liver damage by regulating manganese superoxide
dismutase, an endogenous antioxidant enzyme.

Other speakers addressed how flavonoids, phytochemicals,
and other dietary constituents affect cell-signaling
pathways, contributing to the reduction of oxidative stress
and the prevention of cancer. For example, catechins in tea
may inhibit growth factors implicated in cancer. In rats,
white tea and certain catechins in tea provide some
protection against colon tumors induced by "cooked-meat mutagens." Resveratrol in wine and grapes and isothiocyanates
in cruciferous vegetables induce apoptosis,
or programmed death, in cancer cells. The omega-3
fat DHA suppressed amyloid plaque formation in the
brain when fed to mice that mimic Alzheimer's disease.
Selenium compounds block the cell cycle and lead to
apoptosis in melanoma cells and also inhibit metastasis
of injected melanoma in mice. Additionally, acetyl-Lcarnitine
inhibited inflammation and oxidative stress
in rat astrocytes (cells in the nervous system that
support neurons). Astaxanthin, an orange-colored
carotenoid, ameliorates oxidative stress in the kidney
cells of diabetic mice.

In the final session, scientists discussed mitochondria,
the energy-producing organelles in cells that can be
damaged by oxidants generated within the mitochondria
themselves. Such damage can be attenuated by
glutathione, an endogenous antioxidant, and glutathione
peroxidase, an enzyme that inhibits lipid oxidation in
mitochondria. Mitochondrial dysfunction and defects
have been implicated in neurodegenerative diseases
like Parkinson's. Additionally, loss of calcium regulation
associated with ischemia and reperfusion results in
increased oxidative stress in mitochondria, and the
signaling molecule nitric oxide plays a role in mediating
ischemic damage. (Ischemia refers to the partial or
complete obstruction of an artery, resulting in reduced
blood flow and oxygen supply to the heart and other
tissues. Symptoms may include angina, pain in the
arm, shortness of breath, and nausea.)